No contract is allowed to take away what the law gives you. Either the law says "except on a plane/ship/etc." (which is plausible) or the contract is invalid.
Can you imagine how it would be if every contract you sign had a "I own you now, no backsies"?
That's not what I said though. I just said you're giving away liberties.
For example, at home, I'm free to walk around nude and scream.
On a plane, I'm not.
> No contract is allowed to take away what the law gives you.
That's incorrect. In fact this is exactly what all contracts do.
That sounds like a technicality. You can absolute agree to not do something that would otherwise be lawful. You still have the same rights, but you have other restrictions on you. The two can exist concurrently.